Евстахиева Заслонка [Valve of the Inferior Vein Cava (Eustache), Bna; B. Eustace]

The Eustachian valve (also known as the valve of the inferior vena cava) is a valve located at the point where the inferior vena cava enters the right atrium. It was first described by the Italian anatomist Bartolomeo Eustachio in 1552, which is why it bears his name.

This valve prevents blood from flowing back from the right atrium into the inferior vena cava when the atrium contracts. It consists of two thin petals that are attached to the walls of the vein. The valve opens when the vein fills and closes when the pressure in the atrium exceeds the pressure in the vein.

Thus, the Eustachian valve plays an important role in maintaining unidirectional blood flow from the inferior vena cava to the right atrium. It prevents blood regurgitation and promotes efficient functioning of the cardiovascular system.

Evastachian valve

E. z. is a valve located at the junction of the thin vein with the IVC. From the IVC side, the valve is not covered, since the semilunar recess of the round ligament of the liver (may be absent) does not open into it. On the reverse side it is connected to the neck ring and can freely move forward when inhaling. Therefore, during forced exhalation, communication between the atria on the right side occurs through it (although in the absence of pathological processes in the lungs, it is usually open). With the help of this valve, negative intrathoracic pressure is maintained, which ensures the flow of air from the bronchi to nourish the alveoli of the lungs, and from them into the capillaries of the pulmonary circulation.